284 THE RESEARCHES OF NENCKI AND PAWLOW. [BOOK II. 



blood from the hepatic artery penetrates into the intralobular capil- 

 lary network and, under abnormal circumstances, may keep up the 

 blood-supply of the lobule so as to enable the creature to tide over 

 the period which intervenes until the circulation through the inter- 

 lobular branches of the portal vein is re-established. That the secre- 

 tion of bile can go on for a time when the portal vein alone supplies 

 blood to the liver has been shewn by the observations of a number 

 of observers (Scruff 1 , Yon Asp 2 , Wertheimer 3 ), though an occlusion 

 of branches of the hepatic artery rapidly leads to localised necroses 

 of the liver substance (Cohnheim u. Litten 4 ), through the cutting off 

 of the nutritive supply to vessels, ducts, and connective tissues. 



Some of the facts which prove that, when the portal vein is 

 occluded, the secretion of bile proceeds at the expense of the blood 

 of the hepatic artery, must now be briefly reviewed. In the first 

 instance, cases were observed, in the human subject, in which the 

 portal vein opened into the vena cava inferior below the liver, and 

 yet the secretion of bile did not appear to be interfered with 

 (Abernethy 5 , Lawrence 6 ). In Abernethy's case, the hepatic artery 

 was found to be greatly dilated. In these cases, as the investigations 

 of Kiernan 7 revealed, the lobules were supplied with venous blood 

 through collateral channels and it cannot, therefore, be held that 

 they offered substantial evidence in favour of the view that the 

 hepatic artery is able, unaided, to provide the materials for the 

 secretion of bile. 



Another class of cases includes those (of which a large number 

 have been observed in the human subject) in which, through an 

 inflammatory process, the portal vein has been occlused by a throm- 

 bus, as well as those in which the portal vein has been experi- 

 mentally occluded by the method of Ore. In the latter cases, as 

 Schiff 8 has found, a collateral circulation, enabling portal blood to 

 reach the interlobular portal veins, soon becomes established. For 

 a time, however, the direct access of portal blood to the liver is cut 

 off and yet the secretion of bile continues. The most interesting of 

 all experiments bearing indirectly on this question are those recently 

 performed in St Petersburgh, and to which reference will be made, 

 at greater length, in a subsequent chapter. In these the portal 

 vein was ligatured and, at the same time, a fistulous aperture was 

 established between the portal vein and the inferior vena cava. 

 About one-third of all the dogs subjected to this most difficult 



1 Schiff, op. cit., Pfliiger's Archiv, Vol. in. (1870), p. 598. 



2 v. Asp, ' Zur Anatomie und Physiologie der Leber,' Ludwig's Arbeiten, 1873, 

 p. 124 et seq. 



3 M. E. Wertheimer, ' Sur la circulation intero-hepatique de la bile,' Archives de 

 Physiologie, No. 3, Juillet, 1892, pp. 577587. 



4 Cohnheim u. Litteu, Virchow's Archiv, Vol. LXVII. (1876), p. 153. 



5 Abernethy, Philosophical Transactions, 1793, p. 61. 



6 Lawrence, Med. Chir. Transactions, Vol. xi. (1814), p. 174. 



7 Kiernan, Philosophical Transactions, 1833, u. p. 758. 



8 Schiff, Schweitz : Zeitschriftf. Heilkunde, i. p. 1 (quoted by Heidenhain). 



